[c-nsp] GRE tunnel (inside ICMP fails after two pings) - Wits End

[Chris Jones]

Try turning off keep alive on the Cisco side (“no keepalive").  I’ve seen issues with GRE tunnels to non-Cisco boxen with that enabled (even when the other side supposedly supports it)

Chris

> On 24 Aug 2018, at 9:09 am, David Deutsch <ddeutsch at tsicorp.net> wrote:
> 
> Hoping the list can help with this one.
> 
> I have a basic GRE tunnel between my Cisco ASR1006 and a Linux box.
> 
> On the Cisco side:
> 
> interface Tunnel100
> description Tun 100 - BPT
> ip address 172.16.100.1 255.255.255.0
> tunnel source x.x.136.1
> tunnel destination x.x.x.234
> 
> I have several of these basic GRE tunnels from this router, however this is
> the only one giving me problems.
> 
> The tunnel source is my loopback, I can ping the local 172.168.100.1,
> however when I try to ping the other inside:
> 
> #ping 172.16.100.2
> Type escape sequence to abort.
> Sending 5, 100-byte ICMP Echos to 172.16.100.2, timeout is 2 seconds:
> !!...
> Success rate is 40 percent (2/5), round-trip min/avg/max = 97/105/113 ms
> 
> It always dies after two pings, every time. Additionally, pinging from the
> other side has the exact same results:
> 
> ping 172.16.100.1
> PING 172.16.100.1 (172.16.100.1): 56 data bytes
> 64 bytes from 172.16.100.1: seq=0 ttl=255 time=83.430 ms
> 64 bytes from 172.16.100.1: seq=1 ttl=255 time=88.326 ms
> ... then nothing.
> 
> I've gone as far as to completely rebuild the Linux side with no luck and
> I'm starting to feel that I've missed something basic on the Cisco side,
> except I've used these tunnels for years.
> 
> Any advice/ideas?
> 
> Thanks,
> David
> _______________________________________________
> cisco-nsp mailing list  cisco-nsp at puck.nether.net
> https://puck.nether.net/mailman/listinfo/cisco-nsp
> archive at http://puck.nether.net/pipermail/cisco-nsp/